Why is it when it comes to someone justifying the size of the iPhone then they are incapable of acknowledging there are sizes in between a speedboat and a yacht? Just because a 5" Android phone will exist doesnt mean the manufacturers are getting out of control with their sizes, they are simply experimenting with different models to see what sticks. And for the most part, the trend of phones from 4.3-4.8" has been widely accepted. So theres no need to rally people to say "stop" when they are happy with having options rather than a single size dictated to them.
BTW. As much as people claim 3.5" was perfect and now 4" 16:9 is equally as perfect, IF we were given a size option on the Apple side then it likely wouldnt be a flop because a sizable portion of iPhone users are picking their phone based on the OS they prefer and "settling" for the hardware size that it comes on.